This invention relates to a sludge supplying device for a single type filter press, wherein a sludge feeding nozzle adapted to be fitted in a recess in the side wall of each filter plate so as to feed a sludge between the neighboring filter plates is maintained in a generally constant direction during the movement thereof and even after the filter plates have been opened, thereby facilitating the discharge of cake removed from the filter cloths, the travelling of each filter cloth and the washing thereof.
Generally for a filter-cloth travelling type, single type, filter press, there is prevailingly used a sludge supplying device of the type in which a sludge feeding nozzle is adapted to be fitted in a recess in the side wall of each filter plate, with a filter cloth interposed therebetween. A prior art sludge supplying device of this type is shown in FIGS. 1 and 2. In this device, a sludge feeding nozzle 4 is inserted between two filter cloths 2 and 2' the two clothes being strained between filter plates 1 and 1'. The nozzle 4 is adapted to be fitted in a recess 3 in the side wall of each filter plate 1 or 1', and connected integrally to a sludge supply pipe 5. The sludge supply pipe 5 is mounted on a single support arm 6, which vertically extends along the side wall of filter plate 1 and is pivotally supported at the top end thereof by a pivot pin 7. A separation pin 8 attached to sludge supply pipe 5 is connected to a separation pin 9 attached to filter plate 1' adjacent to filter plate 1 by a separation means 10 such as a chain. With such a sludge supply device, when filter plates 1 and 1' are respectively shifted to an open position after termination of the dehydrating operation, sludge supply pipe 5 is pulled by separation means 10, as filter plate 1' is shifted to an open position, to cause a pivotal movement about pivot pin 7, of support arm 6, whereby the sludge supply pipe is positioned substantially at a mid portion between filter plates 1 and 1'. At this juncture, sludge feeding nozzle 4, because of being integral with support arm 6, assumes a tilted posture relative to the filter cloths, as shown in FIG. 1, thus resulting in the impingement of cake on the nozzle when the cake is discharged through the neighboring filter cloths 2 and 2', or an unwanted contact of filter cloths 2 and 2' with the nozzle upon travelling and washing thereof, leading to a break in the filter cloths.
Where a sludge feeding nozzle 4 of a flat, vertically elongated shape is used to provide an improved sealing effect, even a small angle of pivotal movement of support arm 6 is magnified into a large amplitude at the top and bottom tips of nozzle 4, which causes the nozzle to strongly contact a travelling filter cloth, leading to an expedite break both in the nozzle 4 and filter cloths 2 and 2'. If the spacing between the neighboring filter plates is increased, with a view to preventing a contact of sludge feeding nozzle 4 with filter cloths 2 and 2', an increased over-all length of the filter press and a reduced filtering area per unit floor space would be bound to result. Such is undesirable for the sludge supply device, particularly for use in a filter-cloth travelling type, single type, filter press.